Wireless devices, such as cellular phones and wireless modems, provide a convenient method of communication. Many wireless devices are designed to transmit high frequency signals because of the transmission efficiency and other associated advantages. To transmit a high frequency signal, a wireless device may convert a low frequency signal that represents the input of a user into the high frequency signal for transmission. Also, a wireless device may be required to convert a high frequency signal that it receives from another wireless device and convert the received frequency signal into a low frequency signal so that the converted signal may be processed into an appropriate output form for the user. One method of converting signals is generally known as direct conversion, which refers to a simplified conversion process that uses fewer mixers, which are driven by a phase lock loop oscillator to conduct the conversion process. Direct conversion generally occurs in a transceiver chip of the wireless communications device. The output of phase locked loop oscillator is referred to as “carrier.” During the direct conversion process conducted by a transmitter portion of a transceiver chip, the carrier is modulated with the data to be transmitted.
A communications device using the direct conversion process may be susceptible to unmodulated carrier component that may be mixed in with a transmitted output signal of the transceiver chip. Such a component may be referred to as “carrier leakage.” Carrier leakage may effectively limit the total transmitter power level range in many wireless devices because the level of carrier leakage stays constant even when the transmitter power level is low, and some wireless devices may be required to comply with industry-defined standards that limit ratio between the level of carrier leakage and transmission signals.